So.... I BLEW up my motor.... literally...

You missing any sockets..lol

sorry to hear about this....you have been through a lot with this bike.....from everything i have read and heard,those cams throwing a shim is a freak thing...i ve got 2x cams and have about 800 miles on rebuild and so far so good.....let us know what ya find.....i ve got a valve cover you can have ....its just sitting in garage.....keith...

Sorry to hear about your problem. Not much else that could punch a hole that big other than a shim. That cam is toast as well.

How many times have you checked the valve clearance since the motor was finished.

I have seen other brands of cams (bolt-in's) spit a shim before. The clearance gets to large, and the cam lobe scoops the shim, right out. I have ran up to a .410" lift with the shim on top. I keep the valve clearance on the tighter side. I beleive it's the duration, is the reason. Most cams around 280*-290* have a somewhat pointed nose, then add in the fast valve action. It become a pitching machine!

On new motors, the valve train can shift around alot. That's why it is wise to keep checking them, at frist. That extra, backup valve cover gasket, isn't a waste of money.

Everyone checks their valves on different schedules, I do the frist 30 min., and then on the third day, then once a week until the valve clearance is stable. It's alot of work, I think of it as buying insurance......To protect my investment.

Good luck! Maybe the damage isn't to bad.

yeah, I probably wasn't as diligent with checking valve clearances as I should have been. I have only checked them a couple times since I got the motor running again.
Kinda anxious about getting the cover off tomorrow... I'll post some pics asap...

We can all sit here and speculate all day long.... Take the cover off and inspect for that's the only way to know for sure...


The following is something to think about, no need to reply on them....

Prior to running this motor, manual rotations no binding or knock sounds in the valve cover correct?

What about the camshaft sprockets, are they adjustable or did you install OEM sprockets?

If adjustable, are you 100% positive the cam degreeing was spot on...

When re-building this motor, had you replaced your timing chain and components (top idler, gears, guides, rubber etc...)

Was head, cam caps, cylinder nuts and bolts torque sequence and torques values spot on....

Wonder if timing top idler gear snapped out or something...

Engine pre-lube used....

Camshafts where definitely installed correctly (not 180 out) I know, I know but we get in a hurry, late at night, tired etc... it happens...

Valve clearances where on the money....

Ignition timing was spot on (not way too advanced).


As much as I hate to say this, if this was my motor, remove and split the cases and inspect if something is missing, came up the timing chain galley and got spit out through the cover... Doubtful yes, impossible no...

Does it suck, yup but it is repairable... We all feel your pain but these are old machines and shit does happen...

Good luck...

OMR

the positive thing is it was still running, and well enough to get you home,,
I do agree, look and see what really went wrong, there are way too many parts in the top end that could have caused the problem.
I have seen motors blow that looked like a bomb went off inside them, one of them caused by a loose carb air cleaner stud.

let us know

So here we go... I'll save the official diagnosis til after the pics:

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and yes that IS a Neil Diamond shirt. Don't hate. haha

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